1. Field of the Invention
This invention relates to electrical circuits and, more particularly, to circuitry for detecting a change in the logic level of a signal and for generating a self-timed flag indicative of the change.
2. Discussion of the Prior Art
Memories and other integrated circuits which externally appear static, i.e., responsive to logic levels rather than level transitions, but which internally utilize clock signals for timing control, require some method for detecting input signal transitions.
The conventional method for detecting such transitions utilizes a delay through a series of logic elements to generate brief signal-overlap times and thereby produce short pulses. FIG. 1 illustrates a logic implementation of one such prior art transition detector. The transition detector shown in FIG. 1 utilizes an odd number of stages, sufficient in number to provide the required pulse width. This approach requires careful control of signal delays to ensure detection, that is, to avoid missing pulses that are too brief.